Genetic diversity of Malaysian indigenous Mahseer, Tor douronensis in Sarawak river basins as revealed by cytochrome c oxidase I gene sequences

Document Type : Research articles



Malaysian Mahseer, Tor douronensis, locally known as “kelah” in Peninsular Malaysia or
semah in Sarawak is one of the important Mahseers used for food as well as the aquarium
industry and game fishing. This species is endemic to Malaysian Borneo river basins. The
wild stocks of T. douronensis have declined substantially in recent years, due to over
exploitation, pollution and illegal fishing practices. DNA sequencing based on a partial
sequence of the cytochrome c oxidase I (COI) gene, was used to determine genetic
variation in wild stocks of T. douronensis originated from eight different populations in
Sarawak River Basins of Malaysian Borneo. The highest haplotype diversity was found in
Entabai river population while the lowest were marked in four populations of Lundu,
Terbat, Bau and Kg. Pa Puti. The population structure analyses based on ANOVA or
found low level of intra and high level of inter population variations in samples of T.
douronensis of Sarawak. The presence of unique haplotype in some populations, along with
high FST values indicated that there has been restricted or no migration among the
existing population which were separated by geographical barrier or river systems. The
population structure of the three regions was also analysed using ANOVA and revealed
that most of the variations occurred among regions and among subpopulations within a
region. Population structure of T. douronensis showed high degree of genetic heterogeneity
and appeared to be significantly structured into geographically discrete population.